The present disclosure relates to an electronic apparatus and an image forming apparatus, and in particular to a technique of efficiently monitoring a temperature using a thermopile sensor.
Electronic apparatuses such as an image forming apparatus are configured to maintain the temperature of a fixing unit not lower than a predetermined level, so as to start executing a printing job within a reasonably short time upon receipt of a job instruction from a user. For this purpose, however, the fixing unit, which works at the final stage of the image forming process, consumes a largest amount of power, and therefore reduction in power consumption by the fixing unit is being positively studied, under the growing requirement for power saving. One of the attempts for power saving is implementing a human body detection function using a pyroelectric infrared sensor.
With the human body detection function, the apparatus can be switched to a sleep mode from a ready mode in a state where a human body is not detected, which prevents failure in turning off the apparatus, thus contributing to reducing power consumption. In this case, normally the display unit is turned off in the sleep mode, and therefore the apparatus is configured to turn on the display unit when a human body is detected by the human body detection function, for convenience to users. Although the mentioned configuration is just an example, such human body detection systems that utilize a low power-consumption infrared sensor having a wide detection region, such as a pyroelectric infrared sensor and a thermopile sensor, are widely employed. Arranging the thermopile elements in a two-dimensional array pattern leads to formation of a thermopile array sensor, which is capable of measuring two-dimensional thermal distribution of an object of measurement.
An example of the human body detection systems that employ the thermopile sensor is an apparatus that detects radiant heat from a human body with a thermopile and drives a predetermined load based on a DC detection output from the thermopile, to thereby detect presence of a human body.